Fluid Reservoir With Heat Exchanger

ABSTRACT

The invention relates to a fluid reservoir having a sorption medium. An energy absorbing and/or releasing device is provided for the improvement of the energy balance and for an immediately accessible heat supply from the sorption medium, for the gas release process, during the extraction of fuel from the fluid reservoir. For the intermediate storage of thus transferred energy in the form of differential heat between the filling and emptying of the fluid reservoir, the use of a latent heat reservoir, especially materials having melting temperatures of between 0° C. and 1400° C., is preferred. The use of such a latent heat reservoir enables permanent sufficient supplies of immediately accessible energy for a sufficient fluid extraction from the fluid reservoir, such that a flawless operation of an energy converter operated using the fluid, e.g. in the form of a fuel cell or a gas motor, is always ensured, especially in the event of low ambient temperatures.

The present invention relates to a fluid reservoir, in particular afluid reservoir with a sorption medium as generically defined by thepreainble to claim 1.

PRIOR ART

For storing fluids, especially gaseous fuels for operating motorvehicles, the use of sorption reservoirs, for instance based on metalhydrides or metal organic frameworks (MOFs), is known. when the tank isbeing filled, so-called binding energy is released as heat and has to beremoved. For removing the gas stored in the tank, this differentialenergy must be resupplied, however, so that the aforementioned bondbetween the gas and the sorption medium can be broken up again and toenable the gas to be released for removal.

For introducing this expenditure of energy for withdrawing the gas fromthe sorption tank, the provision of an electric heater or theutilization of waste heat from the engine is currently know

An electric heater increases the load on the battery, which is requiredfor storing energy in reserve, or on a corresponding rechargeablebattery that especially upon starting an engine can as a result beadditionally heavily loaded. The release of the gas from the sorptionreservoir by means of engine heat, in the starting mode of an engine,functions only unsatisfactorily to poorly, because of the comparativelylow temperature of the engine. Especially at cold outdoor temperatures,it can be appreciated that such a procedure is unfavorable or evennonfictional.

OBJECT AND ADVANTAGES OF THE PRESENT INVENTION

It is therefore the object of the present invention to improve a fluidreservoir of the type discussed at the outset.

This object is attained by the characteristics of claim 1. Advantageousand expedient refinements are disclosed in the dependent claims.

Accordingly, the present invention relates to a fluid reservoir, inparticular a fluid reservoir with a sorption medium, which distinguishedin that an energy absorbing and/or emitting device is provided. Thus thebinding energy that is liberated on refueling the sorption reservoir canbe received in the reservoir and carried out of it via suitableadditional components, such as a heating and/or cooling loop, or, forbreaking up the bond again between at least some of the gas and thesorption medium for removal of gas from the tank, this energy can beresupplied to the tank at any time and be immediately available.

The following comments may be made about possible types of reservoirsand reservoir properties: For storing gaseous fuels in motor vehicles,sorption reservoirs based for instance on metal hydrides or metalorganic frameworks (MOFs) may for instance be used. On filling the tankwith the gas, the binding energy is released as heat and must be carriedaway. As a rule, in this process a certain temperature, whichcorresponds to the activation energy for desorption of the gas, must beexceeded.

In latent-heat reservoirs, by utilizing the heat of melting upon achange of phase of a suitable storage material, a high energy densitycan be attained at only a slight temperature rise. Because of the higherenergy density, the reservoir can be designed more compactly than aconventional sensitive reservoir because of the small surface area and alow temperature of the reservoir, the heat losses of the reservoir aresimultaneously reduced. For this purpose, materials for utilizing thelatent heat for melting temperatures from 0 to 1400° C. are preferablyproposed.

For the buffer storage of this thus-transferred energy in the form ofthe differential heat between refueling and emptying of the fluidreservoir the use of a latent-heat reservoir is therefore preferablyproposed. By the use of such a latent-heat reservoir, enough availableenergy for adequate fluid removal from the sorption tank is constantlyavailable, so that at any time, satisfactory operation of the energyconverter operated with this fluid, for instance in the form of a fuelcell or a gas engine, especially at low ambient temperatures, isassured.

To achieve the best possible effect of the energy transfer both uponremoval and upon resupply, it is furthermore proposed that some of theenergy absorbing and/or emitting device is disposed in the interior ofthe fluid reservoir. This can be achieved for instance by means of aline that passes through a plurality of reservoir regions.

Such reservoir regions can be understood for instance to bethree-dimensional regions, extending coaxially to one another in theinterior of the reservoir, that are penetrated for instance by a bundleof pipes, which are preferably uniformly spaced apart, that extendslongitudinally in the interior of the reservoir. However, an arrangementof a spiral bundle of pipes, for instance extending along a longitudinalaxis, is also conceivable; for increasing the efficiency, it may also bedisposed coaxially to one or more further, preferably identicallyoriented, bundles of pipes.

To increase the energy carrier throughput in the interior of this energyabsorbing and/or emitting device, the use of a pump is furthermoreproposed. The energy carrier medium may for instance be acorrespondingly suitable fluid.

For reinforcement for the sake of even faster readiness for operationand/or as a redundant device, a heating element may furthermore beproposed, which serves to overcome at least some of the binding energyfor the release of the fluid bound in the sorption medium. Such a heatermay for instance be an electric heater, but it can also be attained bymeans of a connection to a heating and/or cooling loop of the energyconverter to be operated, so that the waste heat thus to be carried awayby the energy converter, as a result of this coupling to the convertersheating and/or cooling loop, likewise reinforces the energy transfer inthe energy absorbing and/or emitting device.

The thermal coupling between such a cooling loop, for instance an enginecooling loop or a fuel cell cooling loop, and the fluid reservoir canselectively be done with two separate cooling loops, but direct fluidiccommunication of the tube coolant or heating medium loops is alsoconceivable. With a separate construction, the heat transfer can beeffected for instance through an additional heat exchanger. The use ofvalves is advantageous in both cases, since this makes a suitable loopcontrol for various operating states possible.

As an alternative to this first combination, or in addition to it, heatrecovery can also be provided by way of the exhaust gas output by thethermal and/or mechanical energy converter. For this purpose as well, aheat exchanger may be provided, which furnishes the residual heat,present in the exhaust line, as energy for re-releasing the gas storedin the sorption medium, preferably once again reinforced by a pump andconnectable and disconnectable via valves.

EXEMPLARY EMBODIMENT

The present invention will be described in further detail below inconjunction with the accompanying drawing and the description thereof.

Show is:

FIG. 1, a schematic circuit diagram of a fluid reservoir, equipped witha sorption medium, with an integrated energy absorbing and/or emittingdevice and with plumbing interconnection with further functionalcomponents.

In detail, the illustration in FIG. 1 shows a fluid reservoir 1, filledwith a sorption medium 2, and an energy absorbing and/or emitting device3 integrated with it. Wit a heating and/or cooling loop 4, the bindingenergy liberated when the sorpution reservoir I is refueled with gas canbe recovered and buffer-stored in a latent-heat reservoir 5 for laterreintroduction in order to reverse the binding process.

Part of the energy absorbing and/or emitting device passes in the formof a line 6 in the form of a bundle of pipes 7 through a plurality ofinner regions of the reservoir. As a result, the binding energyliberated in refueling can be carried away as well as possible, and forthe case of re-removal of the gas from the tank, it can be resuppliedwith as uniform as possible a spatial distribution, so that a rapid gasrelease from the sorption medium is assured. To increase the efficiencyof the energy absorbing and/or emitting device, the heat carrier mediumintroduced into the line 6, which may for instance be an antifreezesolution, can be made to circulate by means of a pump 8.

For reinforcement in the resupply of heat to the sorption reservoir, oras a redundant heat source, a heater 13 may be provided, which as anexample is integrated here with the line 6 of the heating and/or coolingloop 4. To further optimize the energy balance, the energy absorbingand/or emitting device 3 may communicate with a heating and/or coolingloop 15 of a thermal and/or mechanical energy converter 16. Thiscommunication is represented symbolically here by the connection 14,which for introducing fluid includes a valve 9 in the form of a controlvalve. The introduction of heat from the engine coolant loop is effectedvia a heat exchanger 17.

Additional operating states of the fluid reservoir 1 are possible bymeans of suitable triggering of the other valves 10, 11 and 12. Forinstance, a further heat input into the energy absorbing and/or emittingdevice 3 is possible by way of introducing the exhaust gas heat, removedin an exhaust line 20 and recovered via a heat exchanger 18, of theenergy converter 16 via the line connection 19. The supply of fuel tothe energy converter 16, for instance in the form of a gas engine orfuel cell, is effected, under the control of the two valves 22 and 23,via the fluid line 21.

Thus by means of the energy absorbing and/or emitting device 3 providedaccording to the invention, with the heating and/or cooling loop 4 andthe latent-heat reservoir 5, a possibility is described for optimizingthe energy balance while simultaneously improving the readiness foroperation of a sorption mediun-equipped fluid reservoir 1 by means ofone possible, but not limiting, exemplary embodiment.

1-10. (canceled)
 11. A fluid reservoir, in particular a fluid reservoirwith a sorption medium, provided with an energy absorbing and/oremitting device.
 12. The fluid reservoir as defined by claim 11, whereinthe energy absorbing and/or emitting device has a heating and/or coolingloop.
 13. The fluid reservoir as defined by claim 11, wherein the energyabsorbing and/or emitting device has a latent-heat reservoir.
 14. Thefluid reservoir as defined by claim 12, wherein the energy absorbingand/or emitting device has a latent-heat reservoir.
 15. The fluidreservoir as defined by claim 11, wherein part of the energy absorbingand/or emitting device is disposed in the interior of the fluidreservoir.
 16. The fluid reservoir as defined by claim 12, wherein partof the energy absorbing and/or emitting device is disposed in theinterior of the fluid reservoir.
 17. The fluid reservoir as defined byclaim 14, wherein part of the energy absorbing and/or emitting device isdisposed in the interior of the fluid reservoir.
 18. The fluid reservoiras defined by claim 11, wherein the energy absorbing and/or emittingdevice has a line that passes through a plurality of inner regions ofthe reservoir.
 19. The fluid reservoir as defined by claim 12, whereinthe energy absorbing and/or emitting device has a line that passesthrough a plurality of inner regions of the reservoir.
 20. The fluidreservoir as defined by claim 17, wherein the energy absorbing and/oremitting device has a line that passes through a plurality of innerregions of the reservoir.
 21. The fluid reservoir as defined by claim11, wherein the energy absorbing and/or emitting device includes abundle of pipes.
 22. The fluid reservoir as defined by claim 20, whereinthe energy absorbing and/or emitting device includes a bundle of pipes.23. The fluid reservoir as defined by claim 11, wherein the energyabsorbing and/or emitting device includes a pump.
 24. The fluidreservoir as defined by claim 22, wherein the energy absorbing and/oremitting device includes a pump.
 25. The fluid reservoir as defined byclaim 11, wherein the energy absorbing and/or emitting device has aheating element.
 26. The fluid reservoir as defined by claim 24, whereinthe energy absorbing and/or emitting device has a heating element. 27.The fluid reservoir as defined by claim 11, wherein the energy absorbingand/or emitting device has a connection to a heating and/or cooling loopof a thermal and/or mechanical energy converter.
 28. The fluid reservoiras defined by claim 26, wherein the energy absorbing and/or emittingdevice has a connection to a heating and/or cooling loop of a thermaland/or mechanical energy converter.
 29. The fluid reservoir as definedby claim 11, wherein the energy absorbing and/or emitting device has aconnection to an exhaust line of a thermal and/or mechanical energyconverter.
 30. The fluid reservoir as defined by claim 28, wherein theenergy absorbing and/or emitting device has a connection to an exhaustline of the thermal and/or mechanical energy converter.